As generally known in the art, a large scale inkjet printer has been essentially used in manufacturing various outdoor advertising sign, and recently, which is likely to have been further diversifying or scaling-up, so that it needs to continuously supply a great quantity of ink required for printing.
As shown in FIGS. 1 and 2, a simplified structure of the large scale inkjet printer comprises a printer body 1 having housings 3, each of which is supported by plural supporting legs 2 and in which a carriage bar is horizontally disposed between the housings; a printer head for printing a medium to be printed in an inkjet manner while horizontally moving across the carriage bar; and a cartridge assembly 4 that is mounted to one side of the back of the printer body and that has a plurality of cartridges for supplying ink to the printer head.
The cartridge assembly 4 has a plurality of cartridges 5, which are constituted so as to be placed in parallel, each storing ink including, for example, black, yellow, red or blue-green, etc.
The cartridge 5 in a unit includes a storing pack in which ink is filled, a casing of rectangular parallelepiped for protecting the storing pack, and an operating plate mounted to one side of the storing pack so as to inform of replacement time of the cartridge through a contact of a separate detecting switch upon exhaustion of ink.
Since the cartridge 5, however, is a disposable product, it must be detached from the printer and then replaced by a new cartridge when ink filled in the storing pack is exhausted.
The disposable cartridge 5 of the conventional structure, therefore, has a problem in that it is used to replace it by a new one every time, causing uneconomical aspects and poor workability of replacement of the cartridge 5.
That is, although ink is exhausted from even any one of the cartridges during printing, all operation of the printing must be interrupted, causing working time to be increased and workability thereof to be greatly reduced.
Especially, in the case where the cartridge 5 is replaced by a new one during printing, the printing is interrupted so that serious defects may be generated to the printed matter thus to make re-printing troublesome and expenses for printing considerably increased.